It is located to the west-southwest of the prominent ray crater Tycho, and is attached to the southern rim of the walled plain Wilhelm.

Along the northwestern side is the crater remnant Lagalla, and just to the south is the large walled plain Longomontanus.

The rim of Montanari has been so deeply eroded by impacts that it is now little more than an irregular border around the interior floor.

The satellite crater Montanari D lies across the western rim, and covers part of the interior floor.

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Montanari.